“…Using the DIP method, the microstructures of geomaterials can be identified accurately within a certain resolution. As a result, DIP has been widely applied in the detection of morphological characteristics for geomaterials (Ammouche et al, 2000(Ammouche et al, , 2001Obaidat et al, 1998;Xu et al, 2007a;Yue et al, 1995;Yue and Morin, 1996). As problems of heterogeneous media are so complex that they cannot be solved analytically, further studies have been made to incorporate the DIP technique into numerical methods (Yue et al, 2003(Yue et al, , 2004Armesto et al, 2009;Chen et al, 2004Chen et al, , 2005Chen et al, , 2007Michailidis et al, 2010;Xu et al, 2007Xu et al, , 2008aXu et al, , 2008b.…”